Aug. 10, 2011: Huma Abedin, deputy chief of staff to Secretary of State Hillary Clinton, takes her seat as she attends a dinner in the State Dining Room of the White House. (AP)

In this Sept. 20, 2011 file photo, Huma Abedin, top, deputy chief of staff and aide to Secretary of State Hillary Rodham Clinton, right, during a meeting with leaders for the Open Government Partnership in New York. Republican Sen. John McCain is defending a longtime aide to Secretary of State Hillary Rodham Clinton against unsubstantiated allegations that her family has ties to Egypt's Muslim Brotherhood. (AP)

Sen. John McCain took to the Senate floor Wednesday to defend a well-known aide to Secretary of State Hillary Clinton against accusations by other Republicans that her family has ties to Egypt's Muslim Brotherhood.

McCain, R-Ariz., called the charges made by Rep. Michele Bachmann, R-Minn., and others against longtime Clinton aide Huma Abedin "nothing less than an unwarranted and unfounded attack on an honorable woman." The State Department also commented on the matter Wednesday, calling the accusations "absolutely preposterous."

Abedin is a Clinton family confidante and the wife of former New York Rep. Anthony Weiner, who resigned last year in disgrace following a sex-ting scandal.

Bachmann, a member of the House Intelligence Committee, along with four other Republicans, made the allegations against her in June letters to five national security agencies, demanding a probe over alleged "deep penetration" of the Muslim Brotherhood into the Obama administration.

The allegations, which had not received much public attention until McCain's statement Wednesday, charged that Abedin's late father, mother and brother are tied to Brotherhood groups or operatives, and noted that Abedin has "routine access" to Clinton.

Bachmann also followed up with a 16-page letter Wednesday to fellow Minnesota lawmaker, Rep. Keith Ellison, a Democrat, who had challenged her to substantiate the accusations. Bachmann wrote in the letter that Arab-language media have "widely" reported on her family's ties, and also cited a 2002 law review article that said Abedin's late father was the founder of an institute in Saudi Arabia that had "the quiet but active support" of an official with the Muslim World League. Bachmann wrote that the Muslim World League, in turn, has a "longtime history of being closely aligned" with the Brotherhood.

"For us to raise issues about a highly-based U.S. government official with known immediate family connections to foreign extremist organizations is not a question of singling out Ms. Abedin. In fact, these questions are raised by the U.S. government of anyone seeking a security clearance," wrote Bachmann.

"Given the reasonable assumption that Ms. Abedin has a high-level security clearance, as a member of the House Select Committee on Intelligence I am particularly interested in exactly how, given what we know from the international media about Ms. Abedin's documented family connections with the extremist Muslim Brotherhood, she was able to avoid being disqualified for a security clearance," she said.

McCain publicly blasted the charges on Wednesday, saying Abedin, deputy chief of staff to Clinton, "represents what is best about America."

"I know Huma to be an intelligent, upstanding, hard-working, and loyal servant of our country and our government, who has devoted countless days of her life to advancing the ideals of the nation she loves and looking after its most precious interests," McCain said. "I am proud to know Huma, and to call her my friend."

As for the claims about Abedin's late father, McCain noted that he died two decades ago and that the congresswoman failed to provide "one instance of an action, decision or a public position that Huma has taken while at the State Department that would lend credence to the charge that she is promoting anti-American activities within our government."

"Our reputations, our character, are the only things we leave behind when we depart this earth, and unjust attacks that malign the good name of a decent and honorable person is not only wrong; it is contrary to everything we hold dear as Americans," he continued.

Bachmann, meanwhile, responded Wednesday by saying that the letters written by her and her colleagues had been "distorted."

"I encourage everyone, including media outlets, to read them in their entirety," Bachmann said in a statement. "The intention of the letters was to outline the serious national security concerns I had and ask for answers to questions regarding the Muslim Brotherhood and other radical groups' access to top Obama administration officials." She made no mention of Abedin.